One of the important components of the sponge iron production line in the Midrex process is the recuperator. Midrex recuperator has the role of heat exchange between combustion products exiting from the reformer and three independent streams of combustion air, natural gas and feed gas. The optimal performance of this recuperator is important from various aspects and it is necessary to acquire the technical knowledge of the thermal design of the recuperator for both its design and prediction of its thermal-hydraulic behavior. The current research addresses the thermal design of such recuperators with two design and off-design approaches. In this regard, relevant actions including the development of correlations for thermophysical properties of fluids in the form of polynomial functions of temperature, extraction and use of suitable thermal and hydraulic relations (among the large number of relations provided in the sources) and developing a solution algorithm considering interactions of tube-bundles were implementd. Also, the process of design calculations has been validated utilizing available data. Finally, as case studies, two different designs are presented for a specific set of process conditions.

Two unconverted by-products, fine of pellets and reducing sludge, are produced during processing in sponge iron production Companies. In the present research, possibility of the by products briquetting and also direct charge, along with the reactor feed, into the reduction furnace have been investigated. The mentioned byproducts were changed to the briquettes with more than 6.3 mm size (quarter inch) by briquetting jack machine under 300 bar pressure, and their reducibility and strength were tested during passage from the reduction reactor. Experiments showed, the produced briquettes had a low strength to tolerate inserted stresses during moving in the furnace. Using sodium silicate solution (1.25-5 weight percent) as a binder in the composition of the briquettes, to prevent crushing, increased their strength more than 40 times. To increase total Fe of the samples and reaching a standard level, 15-20% sponge iron  powder was added into the briquettes, increased total iron from 84% to 88% averagely.

A higher bustle temperature in midrex direct reduction process is always desirable due to its positive effect on the productivity and DRI quality. The limit of the bustle temperature is related to the sticking or clustering behavior of oxide pellets during the reduction in the reactor. It has been well estabilished that coating of oxide pellets by a refractory material decreases its tendency to clustering. In this study, the clustering behavior of oxide pellets (produced from Golegohar-Chadormalu iron ore) during reduction at different temperatures was investigated. The effect of coating with different amounts of hydrated lime on the clustering behavior was also examined. Microscopic examination of coated pellets shows a porous, non-continuous layer of Ca(OH)2 being formed on the surface of the pellets. The clustering tendency of coated pellets, measured by the standard sticking test at pilot scale, was much lower, compared with normal (uncoated) pellets, while their reducibility was the same.

Inertial Navigation System (INS) is one of the navigation systems widely used in various land-based, aerial, and marine applications. Among all types of INS, Microelectromechanical System (MEMS)-based INS can be widely utilized, owing to their low cost, lightweight, and small size. However, due to the manufacturing technology, MEMS-based INS suffers from deterministic and stochastic errors, which increase positioning errors over time. In this paper, a new effective noise reduction method is proposed that can provide more accurate outputs of MEMS-based inertial sensors. The intelligent method in this paper is a combined denoising method that combines Wavelet Transform (WT), Permutation Entropy (PE), Support Vector Regression (SVR), and Genetic Algorithm (GA). Firstly, WT is employed to obtain a time-frequency representation of raw data. Secondly, a four-element feature vector is formed. These four features are (1) amplitude of frequency, (2) its ratio to mean of amplitudes of all frequencies, (3) location of frequency in time-frequency representation, and (4) judgment on behaviors of frequency that is obtained by utilizing PE. Thirdly, based on the feature vector, the GA-SVR algorithm predicts amplitudes of all frequencies in the time-frequency representation of the denoised signal. Finally, by employing inverse WT the denoised signal is obtained. In this work, the outputs of the Inertial Measurement Unit (IMU) in ADIS16407 sensor, as a low-cost and MEMS-based INS, have been utilized for data collection. The proposed method has been compared with other noise reduction methods and the achieved results verify superior improvement than other methods.

A direct torque control (DTC) induction motor drive is presented in this paper. Quantization errors of current and voltage measurements are simulated and considered. To reduce the average quantization error and other offset errors of current and voltage measurement and eliminating the increasing integrator errors, a random dither signal is added to the truncating analog to digital converter (ADC) outputs. In this method, the ADC mean error is reduced to zero and therefore, integrator output error is mitigated. The proposed quantization method can improve the digital converter result; thus, this method can decrease the current measurement result. Thus, the torque and flux rippleswere be decreased. The proposed dither injection method can be used in Digital signal processor (DSP) or FPGA implemented applications. Experimental results show the performance of the proposed method.